The Benefits of Tropical Homegardens
What is a Tropical Homegarden?
A traditional Tropical Homegarden (THG) of the Pacific Islands differs greatly from the raised bed or vegetable patch image commonly associated with temperate home edible gardens. A THG is a small-scale agroforestry land use system based on cultural traditions of subsistence living. A THG is in close proximity to a place of residence and tended to by the household members. Plants are grown for personal consumption as food, as well as for medicinal, ceremonial and construction purposes.
In their functioning, THGs benefit larger systems, specifically economic, community, and eco-systems. This article defines the relationships that make up a THG system by outlining the benefits of THGs in these three realms.
Economic benefits
Traditional THGs are production systems that can contribute significantly to the household economy. To a homegardener, the economic value of the crops grown is either what they can be sold for or what he or she would pay to purchase them (Vasey, 1990). Consuming food grown in a homegarden can significantly reduce the percentage of the household income spent on food. THGs can also provide construction materials, medicines, decoration, etc., with low input of money, resources, and time. Clark (1977) noted that in Pacific Island agro-ecosystems, for every calorie of energy invested, returns ranged from 10-20 food calories. Any time saved can also be considered a community benefit because the time saved can be spent on other activities (i.e., with family, sharing knowledge, processing foods, generating additional income, etc.).
The percentage of income saved or derived from homegardens is directly related to the diversity of plants in the garden. For example, the more complete the diet grown in a homegarden, the greater the savings. One study found that the food produced by THGs supplied anywhere from 3% to 44% of the total calorie intake in a household (Torquebiau, 1992). THGs also have great potential to substitute for imports because many energy crops—fruits, nuts and staples such as cassava—can be easily grown in tropical climates. Such energy crops can substitute for imports in those countries or regions that do not meet their own demands for grains and cereals (Vasey, 1990). This reduced dependency on imports not only increases food security, but also buffers against the economic uncertainty of global food prices, while simultaneously supporting local economies.
Beyond the income-saving potential, THGs also have the potential to generate income. Homegardens often produce seasonal surpluses of many crops. If a market exists, homegardeners can sell produce and non-food crops (timber, medicinal plants, etc.) for supplemental income as needed. Certain cash crops may be integrated into THGs, such as cacao, tea, coffee, and vanilla. The economic gain from selling homegarden foods and products varies greatly depending on the size of the garden, the needs of the household, and plant diversity (Nair & Kumar, 2004). For example, in Indonesia the percentage of income generated from the sale of homegarden products ranged from 6.6% to 55.7% of total income (Soemarwoto, 1987).
Community benefits
The benefits of homegardens go beyond property lines and garden walls. The community benefits of THGs may be nutritional, social, and cultural. Often underemphasized, they remain largely unpublicized to beginning homegardeners and policymakers who ultimately dictate the zoning and planning of neighborhoods.
Nutritional benefits
Homegardening can significantly improve health by providing for a diverse and nutritionally-balanced plant-based diet. Most of the nutrient loss from fresh produce is due to postharvest handling, storage, and processing (Harvard, 2010); thus, consuming produce shortly after it has been picked maximizes the nutritional benefits. Homegardens are the pinnacle of fresh and local, as food can be picked right before it is consumed or cooked.
High diversity of crops helps to ensure continuous production and consistency to meet dietary needs. Also, a THG that is planted with mostly perennial crops makes a consistent, self-sufficient and nutritious diet even more feasible. Perennial crops—crops that persist for two or more years—have many advantages over annuals, both in gardening and agricultural systems (Glover, Cox & Reganold, 2007). Perennials have deeper root systems than annuals, allowing them to access subsurface water, outcompete weeds, as well as prevent soil erosion. Thus, edible perennials provide a stable and low input (labor and resource) source of food.
Social benefits
The many social benefits that THGs offer are often vital to building and maintaining community structure and values. While a large percentage of THG production is consumed domestically (Soemarwoto, 1987), the tendency of THGs to produce surpluses leads homegardeners to share garden bounty within their community. Such sharing leads to the maintenance of social ties within a community (Thaman, 1990), as well as the spread of nutritious foods and healthy habits. This was confirmed in interviews with tropical homegardeners, expressing that they share or "give away" a large portion of their garden produce to friends, families, and neighbors. One study has estimated that that 64% of households with homegardens in the Pacific Islands share their bounty with friends and extended family (Thaman, 1990).
Another social benefit is the educational value of THGs. Children learn at an early age about how to grow food and where the foods they eat come from as well as continue agricultural traditions. Thus, THGs have the potential to fill large gaps left by standardized education, as this kind of information and type of learning is largely absent from school curricula. Additionally, a THG has recreational value as a result of the physical activity inherent in maintaining a garden. Homegardens in Java have been documented for use as playgrounds as well as sites for social gatherings (Christanty, 1990).
In addition to the health benefits, homegardens of all types have been shown to promote positive mental health. This has led to the development of a field of medicine known called horticultural therapy, which promotes the practice of gardening to increase human well-being and provide assistance to people with mental illnesses (American Horticultural Therapy Association, 2011). Additionally, the sentimental value of homegardens can be very comforting to people, especially to immigrants. In this respect, homegardens offer a way of staying connected with one's cultural traditions (described in further detail in the next section). Along with all of these benefits comes the confidence gained by being able to grow one's own food and increase family self-sufficiency (Thaman, 1990). This is a common sentiment of homegardeners as well as strong motivation for beginning homegardeners.
Cultural benefits
THGs also offer cultural benefits to families and communities. Whether food, medicinal, religious or ceremonial plants, families and communities can "grow" and maintain cultural traditions with a THG. Homegardens allow people to grow ingredients for a traditional diet that they may not be able to find in stores. Religious and ceremonial plants that may be hard to find commercially can also be grown. Abdoellah (1990) stresses the socio-cultural functions of THGs for magical and religious values. Additionally, THGs are places where younger generations can participate in religious rituals and cultural ceremonies as well as learn cultural values from elders in their family and community (Hisyam, Martadihardja, & Suharto, 1978).
Environmental benefits
The environmental benefits of THGs include all the benefits of keeping an area forested or planted. These include sequestration of carbon by plants, soil building, protection against land erosion, and decreased water runoff (Elevitch & Wilkinson, 2000). By keeping areas planted and not paving them, the ground remains permeable and thus rainwater is able to become groundwater; this replenishes the water table, and effectively maintains local hydrological systems. By planting trees near and around structures, THGs can provide shade for people and animals, increasing the productivity of livestock (USDA, 2011), while also helping to regulate the temperature inside structures, keeping them cooler in the heat and warmer in the cold (Mollison, 1990).
THGs are characterized by high biodiversity, sometimes coined "agro-biodiversity," meaning that many plants are grown and managed for agricultural yields (Galluzi, Eyzaguirre & Negri, 2010). THGs are by definition polycultures (more than one crop is grown), with high species variability valued for its consistent productive utility and convenience; this implies not only diversity in species but also diversity in annual and perennial plants.
There are many potential associated benefits, but are THGs sustainable?
It is the inherent ability of THGs to provide a diverse spectrum of benefits that makes a THG a sustainable land use system. In this context, sustainability is defined as the self-sufficiency of a system through the conservation and perpetuation of both natural and human resources. Human resources are the cultures, traditions, and social fabric of a given society. THGs have been shown to provide for family and community needs for food, fiber, medicine, and even income, without depleting the resource base and in many cases even adding to it (Torquebiau, 1992).
A THG can increase a household, family, or individual's self-sufficiency, decrease dependence on imported food and inputs (fertilizers, pesticides, etc.), as well as set an entire community on track towards a self-sufficient food system. A homegarden can be a buffer against inflation, increases in fuel prices, natural disasters, and personal economic hardships (FAO, 2010). Community food security is achieved "...when all citizens obtain a safe, personally acceptable, nutritious diet through a sustainable food system that maximizes healthy choices, community self-reliance and equal access for everyone" (Bellows and Hamm, 2003). This can be achieved through the creation and support of THG systems.